The Liston laboratory works on regulatory T cells. These are a type of white blood cell that act to suppress the rest of the immune response, preventing spontaneous autoimmune disease and acting as a rheostat to control just how active our immune system is. The number of these cells in our blood goes up as we get old, which may contribute to the immune-suppressed state of older persons. We seek to understand these cells, using both patient material and mouse models, so that we can harness their power to fine-tune the immune system for healthy ageing.
Mutations in all subtypes of the inositol 1,4,5-trisphosphate receptor Ca release channel are associated with human diseases. In this report, we investigated the functionality of three neuropathy-associated missense mutations in IPR3 (V615M, T1424M, and R2524C). The mutants only exhibited function when highly over-expressed compared to endogenous hIPR3. All variants resulted in elevated basal cytosolic Ca levels, decreased endoplasmic reticulum Ca store content, and constitutive store-operated Ca entry in the absence of any stimuli, consistent with a leaky IPR channel pore. These variants differed in channel function; when stably over-expressed the R2524C mutant was essentially dead, V615M was poorly functional, and T1424M exhibited activity greater than that of the corresponding wild-type following threshold stimulation. These results demonstrate that a common feature of these mutations is decreased IPR3 function. In addition, these mutations exhibit a novel phenotype manifested as a constitutively open channel, which inappropriately gates SOCE in the absence of stimulation.
The lack of T cell infiltrates is a major obstacle to effective immunotherapy in cancer. Conversely, the formation of tumor-associated tertiary-lymphoid-like structures (TA-TLLSs), which are the local site of humoral and cellular immune responses against cancers, is associated with good prognosis, and they have recently been detected in immune checkpoint blockade (ICB)-responding patients. However, how these lymphoid aggregates develop remains poorly understood. By employing single-cell transcriptomics, endothelial fate mapping, and functional multiplex immune profiling, we demonstrate that antiangiogenic immune-modulating therapies evoke transdifferentiation of postcapillary venules into inflamed high-endothelial venules (HEVs) via lymphotoxin/lymphotoxin beta receptor (LT/LTβR) signaling. In turn, tumor HEVs boost intratumoral lymphocyte influx and foster permissive lymphocyte niches for PD1 and PD1TCF1 CD8 T cell progenitors that differentiate into GrzBPD1 CD8 T effector cells. Tumor-HEVs require continuous CD8 and NK cell-derived signals revealing that tumor HEV maintenance is actively sculpted by the adaptive immune system through a feed-forward loop.
Inborn errors of immunity are a heterogenous group of monogenic immunological disorders caused by mutations in genes with critical roles in the development, maintenance or function of the immune system. The genetic basis is frequently a mutation in a gene with restricted expression and/or function in immune cells, leading to an immune disorder. Several classes of inborn errors of immunity, however, result from mutation in genes that are ubiquitously expressed. Despite the genes participating in cellular processes conserved between cell types, immune cells are disproportionally affected, leading to inborn errors of immunity. Mutations in DNA replication, DNA repair or DNA damage response factors can result in monogenic human disease, some of which are classified as inborn error of immunity. Genetic defects in the DNA repair machinery are a well-known cause of TBNK severe combined immunodeficiency. An emerging class of inborn errors of immunity is those caused by mutations in DNA replication factors. Considerable heterogeneity exists within the DNA replication-associated inborn errors of immunity, with diverse immunological defects and clinical manifestations observed. These differences are suggestive for differential sensitivity of certain leukocyte subsets to deficiencies in specific DNA replication factors. Here, we provide an overview of DNA replication-associated inborn errors of immunity and discuss the emerging mechanistic insights that can explain the observed immunological heterogeneity.